How to use DateTime.UtcNow inside javascript function to display javascript clock?

How to use DateTime.UtcNow inside javascript function to display
javascript clock?

There is a pretty simple javascript clock like below
<script>
function startTime() {
var today = new Date();
var h = today.getHours();
var m = today.getMinutes();
var s = today.getSeconds();
// add a zero in front of numbers<10
m = checkTime(m);
s = checkTime(s);
document.getElementById('clockSpan').innerHTML = h + ":" + m + ":"
+ s;
t = setTimeout(function () { startTime() }, 500);
}
function checkTime(i) {
if (i < 10) {
i = "0" + i;
}
return i;
}
</script>
But it uses browser time settings. Instead i want to use server time.
How can i do something like this ?
var today = new Date(<%=DateTime.UtcNow%>);
It gives error like this

asp.net 4.5